1. Field of the Invention
The present invention relates to a technology for determining a plurality of words to reflect user interest.
2. Description of the Related Art
Many technologies for information retrieval have conventionally been proposed. For example, a technology is widely used for retrieving a document containing a word designated as a search key by a person who conducts a search.
Advanced technologies have also been proposed as follows. When a sentence is input from a user together with an image, information on relation between words in the input sentence is extracted by a related information extraction part, and is recorded in a related-information recording part. Thereafter, when a new sentence is input, related information in the input sentence is extracted, the extracted related information and the related information recorded in the related-information recording part are compared, and the image associated with similar related information is presented (Japanese Laid-open Patent Publication No. 2008-242515).
A set of candidate document information including at least one piece of document information is retrieved from a set of document information according to the relationship between a word included in a retrieval request and a word included in each piece of document information in the set of document information. Document information related to the retrieval request is retrieved from the set of the candidate document information according to the relationship between the words in the retrieval request and the relationship between the words in each of the candidate document information (Japanese Laid-open Patent Publication No. 2003-281183).
A word is designated, retrieval is performed and a document group to be an object is selected. The document is subjected to a morphological analysis, words are extracted and a word under consideration is selected on the basis of the number of frequencies. The cooccurrence relations (cooccurrence graph) of the word under consideration are detected in the sentence unit of each document. A cooccurrence graph included in many sentences is selected as a conceptual graph, and the conceptual vector of a document to be written is decided as to whether to include the conceptual graph. A document is classified and displayed according to the conceptual vector so that the document may be selected (Japanese Laid-open Patent Publication No. 2002-056009).
In the meantime, while a user reads a document, he/she sometimes desires to refer to another document which is related to the document read by him/her and is of interest to him/her. Alternatively, while a user reads a document, he/she sometimes desires to refer to another document which is related to the document read by him/her and is of interest to another user.
In such cases, the user probably conducts a search by using, as a search key, a plurality of words reflecting the interest. The use of words makes it possible to refine the search for documents to be referred to.
However, each user has its own interest therefore different needs. It is thus difficult to determine a plurality of words used as the search key.
Meanwhile, technologies have been proposed for determining on which part of a document a user focuses attention by detecting the current page or the line of sight of the user. Such technologies, however, are extensive.